Centrifugal casting process



Oct. 17, 1961 J. H. BEYER 3,004,314

CENTRIFUGAL CASTING PROCESS 5 Sheets-Sheet 1 Fil ed Sept. 17. 1959 M I i I IN V EN TOR.

Jouu H. BzYcR AT TO Y Oct. 17, 1961 J. H. BEYER 3,004,314

CENTRIFUGAL CASTING PROCESS Filed Sept. 1'7. 1959 5 Sheets-Sheet 2 IN V EN TOR.

JoHu H. Bsvez- AT TO NEV Oct. 17, 1961 Filed Sept. 1'7. 1959 J. H. BEYER CENTRIFUGAL CASTING PROCESS 3 Sheets-Sheet 3 INVEN TOR.

Jam! H. Bsvsz 3,0fl4,3l4 CENTRHFUGAL CASTENG PROCESS John H. Beyer, Beverly, Nl, assignor to United States Pipe and Foundry Company, Birmingham, Ala, a corporation of New Jersey Filed Sept. 17, 1959, er. No. 849,638

4 Claims. (Ci. 22--2tiil.5)

In the centrifugal casting of pipe in horizontal metal molds by the method disclosed in Patent No. 2,853,755, the molten metal is poured into the mold through the core in the bell end of the mold by means of a horngate. The horngate is provided with a core setting means so that a core can be set in position around the spout of the horngate while the mold carriage is withdrawn from the horngate during extraction of the previous casting and coating of the mold. When the mold carriage returns to casting position, the core slips into place in the bell cavity and is held in place by the core setter on the horngate spout during the casting of the pipe. The horngate remains in position until the metal in the mold has solidified in order to hold the core in position in the mold. After the metal has solidified, the pipe is held stationary and the mold carriage moved away from the horngate effect ing extraction of the casting. The mold is then moved toward the horngate and during this stroke it is coated with a refractory, insulating coating.

During the time that the extraction and coating are taking place, the operator must cool the iron splinter in the horngate, remove the splinter, brush out the horngate, apply a new layer of blacking to the horngate interior and set a new core in place around the spout onto the core setter. These steps may often require more time than is required for the extraction and coating, and if the operation is to Work smoothly, the mold carriage must not return to the horngate until the core is in place on the core setter. In such instances it is necessary to hold the mold carriage at the end of the extraction step to permit completion of the above operations by the operator before it is returned to the horngate. On the other hand if the horngate is movable and is moved back from pouring position, the mold carriage may return to casting position immediately, but the casting operation must still be held up until the horngate is prepared and moved into position. Thus it can be seen that if the casting cycle is to be cut to a minimum time, the extraction and coating must be completed without any intermediate delay and casting must start as soon after the mold carriage returns to casting position as possible. i As mentioned previously if the core is held in place by the horngate, the horngate must remain in position until solidification is complete. Since the metal is quickly dumped into the mold, there is no need for the horngate to remain in place during the spinning which follows except that it must remain in place to hold the core in position. The spinning during solidification takes up to 50% or better of the total cycle time, so if the horngate could be withdrawn during this time the operator would have plenty of time to prepare the horngate and place the core for the next casting cycle before the extraction of the pipe and coating of the mold are complete. In addition, the withdrawal of the horngate immediately after pouring would prevent overheating of the horngate with resultant increased life and reduced maintenance.

Accordingly the principal object of this invention is the provision of a method for casting bell end pipe wherein the horngate is withdrawn from the mold during the spinning of the pipe.

A further object of this invention is the provision of a method for casting bell end pipe in which the core is held in place in the mold independently of the horngate.

Bfiflifii l Patented Oct. 17, 1961 Another object of this invention is the provision of a casting apparatus which will permit withdrawal of the horngate immediately after pouring.

A still further object of this invention is the provision of a casting apparatus having means for holding the core in place during spinning which are independent of the horngate.

A specific object of this invention is the provision of centrifugal latches which hold the bell core in place during spinning.

Further objects and advantages will be apparent from a consideration of the description taken in view of the drawings in which:

FIGURE 1 is a cut away view of the bell end of a casting machine showing an embodiment of the invention wherein the core is in position to be inserted in the bell end of the mold.

FIGURE 2 is a cut away view of the casting machine of FIGURE 1 after the core has been positioned and the mold brought up to casting speed.

FIGURE 3 is a cut away view of the casting machine of FIGURES 1 and 2 after the molten metal has been poured into the mold and the horngate withdrawn. This figure also shows a partial section of the end of the horngate and the core setting mechanism.

Referring now to FIGURE 1 there is shown a cut away view of the bell end of a casting machine embodying the core setting mechanism of this invention which is suitable for practicing the claimed process. Only the bell portion of the casting machine is shown since the structure of casting machines is well known to those skilled in the art, and it is obvious that the core setting mechanism of this invention may be adapted for use with casting machines of varied designs. Also, while the invention is described in connection with the casting of bell end pipe, it will be obvious that it is also applicable to the casting of plain end pipe as well.

Metal mold 1 is rotatably mounted, by means not shown, in water box 2 and is fitted with bell flange 3. The bell flange 3 differs from that ordinarily used in that it is provided with three or more centrifugal latches 4 evenly spaced around its circumference. The centrifugal latches 4 aremounted in slots 5 cut in hell flange 3 by means of pins 6 which are held in place by set screw 6. One end of each centrifugal latch terminates in a hook 7 while the opposite end is provided with weights 8. The latch 4 is positioned to permit hook 7 to hook over lip 9 of bell flange 3 as shown in FIGURES 2-4. In order to keep the hook ends 7 clear of the bell cavity except during rotation of the mold, pretensioned helical spring couplings, not shown, are provided between pins 6 and bell flange 3 to hold the latches in the position shown in FIGURE 1 until centrifugal force becomes great enough to overcome the pull of the springs. Of course, a coil spring drawn between weighted end 8 of the latches and the opposite portion of the bell flange would also be satisfactory.

Opposite the end of the water box 2 horngate 10 is slidably mounted on a shifter plate 11 which is movable in the direction of the longitudinal axis of the water box by means of pneumatic cylinder 12. Spout 13 of horngate 10 is provided with a flange 14 to which is bolted core setter l5. Seated on core setter 15 are core 16 and back up plate 17. Maintenance and repair of the horngate and core setter may be simplified by attaching flange 14 to shifter plate 11 instead of the horngate thus permitting either to be removed separately.

Referring now to FIGURE 3, the core setter 15 is seen to have a fixed, drum shaped housing member 13 bolted to flange 14 that is attached to spout 13 of the horngate. Inside the drum 18 there is mounted bearing housing 20 by means of studs 21 extending through rubber mounts 22 seated in holes 19 which are equally spaced about the periphery of the drum. These rubber mounts are used to dampen vibrations and to provide a somewhat flexible structure, to, accommodate any misalignment of horngate and mold and to accommodate variations in cores. Bearing 23, which may be a graphite impregnated bushing or any other suitable type bearing, such as ball or roller bearings, is seated between bearing housing 20 and rotatable core shaft 24, the latter being designed to receive core 16 and back up plate 17 on lands 16' and 17' respectively. Core shaft 24 is kept from becoming detached from the core setter by means of annular ring 25 locking behind bearing housing 20, annular ring 25 being bolted to the rear of core shaft 24 so as to form a flange.

In operation, the operator prepares the horngate for the next cast by cooling and removing the iron splinter, brushing out and blacking the interior, and setting a core and backing plate on the core setter. In the meantime, the previous pipe cast has been extracted from the mold and the mold has been prepared for the next cast. At this point, the mold and horngate are in the position shown in FIGURE 1 and the casting machine is ready to begin another casting cycle. Of course, the horngate could be moved forward before the mold is returned, in which case, the core would enter the bell of the mold as it returned to casting position. However, it is preferable to move the horngate forward after the mold has returned to reduce likelihood of damage to the core.

The horngate is then moved forward by means of cylinder 12 to the position shown in FIGURE 2 to seat the core in the end of the mold, and the mold is brought up to casting speed. The rotation of the mold causes the weighted end 8 of latches 4 to be thrown outward thus causing hook 7 to press firmly against back up plate 17 which is provided to hold core 16 in place without damage from the latches. At this point, the molten metal may be poured into the mold where it becomes distributed along the length of the mold. Alternatively, if it is desirable to cut bearing Wear to a minimum, it is possible to retract the horngate slightly just before the molten metal is poured into the mold through horngate 10, to either relieve the bearing 23 of axial thrust from the core shaft 24 or to free the core shaft 24 from core 17. Of course, only slight retraction is required to relieve axial thrust on the bearing, whereas, a larger movement is necessary to completely unseat the core from the'core holder.

After the molten metal has been poured into the mold through the horngate, the horngate has served its purpose and is retracted to the position shown in FIGURE 3.leaving the core 16 firmly held in place in the spinning mold by latches 4. Once the horngate is retracted, the operator can commence preparing it for the next cast which may include cooling and removing the iron splinter, brushing out the horngate, and applying a coating of blacking in addition to seating acore and a back up plate on the core setter. Meanwhile the mold is kept rotating until the molten metal is solidified, at which time mold rotation is stopped. As the mold speed decreases, the centrifugal force on the latches decreases also, and they fall back to the position shown in FIGURE 1. This frees the back up ring and it is free to fall out of the mold. The ring may be caught on a metal rod, not shown, which is moved into position either manually or by any suitable mechanical means. As soon as the mold has stopped rotating, the mold carriage is retracted over a fixed pushout lance mounted at the spigot end of the mold, as taught in the previously mentioned. patent, to extract the pipe from the mold. The mold is then withdrawn from the pushout lance to return it to casting position, and the mold coating, if a mold coating is used, is applied during this movement of the mold carriage.

By the time the mold carriage completes the Withdrawal stroke, the operator will have the horngate prepared for the next cast. With the mold in position andthe core seated on the core setter, the casting machine is ready to go through another cycle without any delay. The fact that the horngate can be withdrawn from the mold as soon as the molten metal is poured provides the operator with ample time to' prepare the horngate before it is needed again and prevents any delay caused by inadequate time to prepare the horngate. In addition, it is apparent that the time the core holder is rotating is reduced with a resultant reduction in wear, and the quick withdrawal of the horngate prevents both the horngate and core setter from becoming overheated.

It is apparent from the foregoing that the invention provides a means for holding acore around the spout of a horngate, seating the core in the end of a mold, and holding the core in place in the end of the mold while the horngate is withdrawn from the mold. Although I have illustrated and described herein but one preferred embodiment of the apparatus, it will be obvious to those skilled in the art that changes in structure and substitution of equivalent means may be made, For example, the means used to hold the core in place need not rely upon centrifugal force for its motive force and any suitable mechanism, operated mechanically, electrically or any other suitable way, could be used in place of the centrifugal latches to hold the core in place when the horngate is withdrawn from the mold. Accordingly, it is not intended that the invention be limited to the use of centrifugal latches, and such modifications as may be made without departing from the spirit and scope of the invention as defined in the appended claims are deemed to be part of the invention. 7

I claim:

l. A process for casting pipe centrifugally in horizontal molds comprising: rotatably mounting a core about the spout of a horngate; seating said core in the mold by introducing simultaneously into theend of the mold the spout and the, rotatably mounted core; rotating the mold; engaging means for securing the core in place in the end of the spinning mold; pouring molten metal into the rotating mold through the horngate; retracting the horngate spout from the spinning mold without extracting the core from the mold; continuing rotation of the mold until the metal is solidified; stopping mold rotation; disengaging said means for securing the core; and extracting the solidified pipe.

2. A process for casting bell end pipe centrifugally in horizontal molds comprising rotatably mounting a bell core about the spout of a horngate, introducing simultaneously into the bell end of the mold the spout and the rotatably mounted core, rotating the mold, securing the core in place in the bell end of the spinning mold by means permitting withdrawal of the horngate and means forrotatably mounting the core about the horngate, pouring molten metal into the rotating mold through the horngate, retracting the horngate spout from the spinning mold, leaving the core securely in place in the mold continuing rotation of the mold until the metal is solidified, stopping mold rotation, releasing the core, and extracting the solidified pipe.

3. A process for casting pipe centrifugally in horizontal molds comprising: rotatably mounting a core about the spout of a horngate; introducing simultaneously into the end of the mold the spout and the rotatably mounted core; rotating the mold; engaging means for securing the core in place in the end of the spinning mold; partially retracting the horngate spout from the mold and core; pouring molten metal through the horngate; retracting the horngate spout from the mold; continuing rotation of the mold until the metal is solidified; stopping mold rotation; disengaging said means for securing the core in place; and extracting the solidified pipe.

4. A process for-casting bell end pipe centrifugally in horizontal molds comprising rotatably mounting a bell re about the spout 9f a horngate, introducing simultaneously into the bell end of the mold the spout and the core, rotating the mold, securing the core in place in the bell end of the mold, partially retracting the horngate spout from the mold and core, pouring molten metal through the horngate, retracting the horngate spout from 5 the mold, continuing rotation of the mold until the metal is solidified, stopping mold rotation, releasing the core, and extracting the solidified pipe.

References Cited in the file of this patent UNITED STATES PATENTS 

